The present invention relates to the clamping of workpieces in general, and more particularly to an arrangement for clamping (maintaining firmly in position) lumber elements, such as tree trunks, lumber beams or the like, during the processing thereof, especially those which are integrated into a sawing installation.
Currently, relatively large tree trunks, lumber beams or the like which are to be subdivided in a sawing installation into boards, planks, small beams or the like are held in position by clamping wedges which act on the lumber element from above and from below.
This conventional approach brings about the disadvantage that the clamping wedges penetrate, dig into or otherwise deform the lumber element to be processed and thus damage the surface region of the lumber element. Inasmuch as the tree trunk being processed is turned after each sawing or cutting operation about its longitudinal axes by a quarter of its circumference, the above-mentioned penetration of the clamping wedges into the lumber element, and thus the attendant damaging of the boards or the like cut from the lumber element, occurs time and time again during each clamping operation following such turning.
A further disadvantage of the use of the clamping wedges resides in the relatively low utilization of or yield from the cross section of the lumber element, inasmuch as the cross section of the lumber element can be sawed only to an extent permitted by the clamping wedges, that is until the path of movement of the saw relative to the lumber element during the sawing operation reaches the clamping wedges. After that, what remains of the original lumber element is basically waste or refuse wood. Yet, especially nowadays, with the relatively high lumber prices, it is desired to utilize the valuable lumber material to the utmost possible extent.